> I don't get the point you're making
Just that Emacs was written almost a half century ago, and is still thriving despite being written in a language (LISP) that is basically obsolete.
> My argument is that Rust is certainly going to remain relevant for the next 20 years or so
Maybe, maybe not. Look at how quickly Perl (so promising to begin with) disappeared to be replaced by Python. Many new languages have tried, and continue to try, to replace C++ as a better alternative, and I'm sure the next 20 years will see more popup too. Is Rust the one?
If the likelihood of being around in 20 years with a still up-to-date library/tool ecosystem was the main decision making factor, then Java would probably be a safer bet.